Fingerprint identification refers to an identification mode of comparing a scene fingerprint of a person with other pre-stored fingerprint templates to verify the true identity of the person.
The so-called fingerprint template records complete information of fingerprint feature points, including coordinates, attributes, angles, even crest line widths and other information of the feature points. The establishment process of a typical fingerprint template is as follows: collecting a human fingerprint image through a fingerprint reading device, and processing the collected original image to make the same be clearer; then extracting the fingerprint feature points (the feature points are generally endpoints, crunodes, central points and the like of fingerprints), obtaining data description (coordinates, attributes, angles and the like, namely, the feature point information) of the geometric meaning of the feature points, and finally storing the formed fingerprint template. After being collected, the scene fingerprint image will be processed to extract the feature points to obtain the feature point information. Furthermore, the feature point information of the scene fingerprint and the feature point information of the fingerprint template are compared to complete a fingerprint identification process. Accordingly, the fingerprint template is a core data structure of a fingerprint identification method.
Currently, the establishment of various fingerprint identification methods is based on fingerprint templates with complete feature point information, that is, the fingerprint template records the complete feature value information of the feature points, including coordinates, attributes (i.e., the above-mentioned endpoints, the crunodes, the central point and the like), angles, even crest line widths and other data of the feature points. The schematic diagram of a structure of a piece of typical existing fingerprint feature point information is as shown in FIG. 1, the lengths of various data therein can be set according to actual conditions, for example, the data length of an angle is 8 bits in FIG. 1 and can be set to 9 bits or 7 bits in actual conditions, and here it is illustrative. Such existing fingerprint template has an insuperable defect: since the fingerprint template records the values of the complete feature point information of the feature points, once the fingerprint template is leaked, the fingerprint template may be used by malicious people to restore fingerprint images according to the information of the fingerprint template, or make fingerprint images containing the same feature points. This causes risks to the security and privacy of users. Various fingerprint identification methods applied currently have such problem.
Thus, a method is proposed for adding hash points in the fingerprint template to protect the information in the fingerprint template, however, this method has the defects that, first, the fingerprint template cannot be updated, since true points of the template generated by the method are invariable, and the hash points are randomly generated, an attacker can easily obtain the true points when obtaining two or more templates; and second, a large number of hash points (generally larger than 10 times of real fingerprint feature points) need to be added in the fingerprint template, resulting in an increased data volume, the difficulty of the algorithm in the comparison process will be correspondingly increased, and the fingerprint template still has complete feature point information, so that the defect that the feature point information is restored to the fingerprint cannot be overcome completely.